Breaking barriers in smart metering with Wi-Fi HaLow

Wi-Fi HaLow is a future-proof connectivity solution for the evolving needs of smart grids, from real-time energy control to behind-the-meter services, writes Tim Colleran.

Over the past 15 years, smart electric meters have become widely adopted, evolving alongside the networks that connect them. As we move into the future, the shift toward distributed generation and energy storage, coupled with the increasing reliance on intermittent sources like wind and solar, will drive even more change.

The fluctuations in energy production in particular create a need for real-time grid adjustments, where smart meters will take on a more dynamic role, managing home energy consumption in near real-time. For example, in scenarios where wind energy suddenly drops, the grid may struggle to charge electric vehicles (EVs) and power residential systems simultaneously. In these moments, smart meters will evolve into real-time energy managers, capable of optimising home energy use and even drawing power when necessary.

For this vision to become reality however, several technological advancements are necessary. Smart meters will require greater processing power for faster decision-making, along with targeted AI at the edge to handle complex tasks. Improved connectivity within the home is also critical – meters will need to communicate seamlessly with appliances, EVs, storage batteries and solar inverters.

Additionally, the backhaul network will need a significant upgrade, with more throughput and lower latency required to enable real-time energy control. Today, most existing networks struggle to meet these demands. Wi-Fi HaLow, a sub-GHz version of wi-fi, emerges as a highly promising solution capable of supporting the connectivity and performance needs of this future energy ecosystem.

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Wi-Fi HaLow, also known as 802.11ah, offers several key advantages over traditional 2.4GHz wi-fi, making it ideal for smart metering and smart home applications. By operating at a lower frequency, Wi-Fi HaLow offers extended range and better penetration through obstacles like walls and floors, making it especially suited for environments where traditional wi-fi might struggle.

Additionally, Wi-Fi HaLow supports lower power modes, mesh networking and the ability to connect thousands of clients per access point, while maintaining the robust security and native IP functionality familiar to wi-fi users. Although its throughput is lower, typically in the 10-20Mbps range, this is more than sufficient for whole-home coverage and applications like real-time energy management and communication with appliances, EVs and home energy systems.

Wi-Fi HaLow: range, connectivity and efficiency

When comparing Wi-Fi HaLow to 2.4GHz wi-fi for behind-the-meter smart home services, Wi-Fi HaLow shines in both range and penetration. Due to the higher free space loss at 2.4GHz, signals attenuate much faster, resulting in shorter range. In contrast, Wi-Fi HaLow’s narrowband channels and sub-GHz frequency can achieve ten times the range for the same power output. This makes it highly effective at penetrating walls, which is crucial for ensuring reliable connections from the smart meter to in-home devices.

To get from a meter into the home and to the access point, a wireless signal will typically pass through three to five walls. With traditional 2.4GHz wi-fi, signals often degrade or drop entirely after passing through multiple walls, leading to intermittent connectivity or the need for wi-fi extenders and mesh systems. Wi-Fi HaLow, with its penetration and range, eliminates these issues, offering whole-home coverage directly from the meter with minimal infrastructure requirements.

On the utility side, the meter’s communication to the backhaul network primarily facilitates billing and grid management through frequent data readings. Today’s backhaul technologies vary widely, including 400MHz radios, 900MHz Wi-SUN mesh networks, LoRa and LTE, depending on the region and population density. However, the most common solutions are the 900MHz Wi-SUN mesh networks and LoRa WAN, both of which are designed to support low-power, long-range communications.

Wi-Fi HaLow, with its ability to provide reliable, long-range connectivity, presents a strong case as an optimal technology for smart meter-to-utility communications, offering greater versatility and performance where other technologies may fall short.

Wi-Fi HaLow: Pushing legacy smart grid technologies into the future

While technologies like LoRa, Wi-SUN, and LTE have supported smart grid infrastructure for years, Wi-Fi HaLow is emerging as a versatile and comprehensive solution, poised to bring these legacy systems into the future.

For example, Wi-SUN mesh networks are commonly deployed in urban environments and offer scalability, high density communication but require complex infrastructure. As a result, they often face challenges with network latency and range. What’s more, for a smart grid deployment, Wi-SUN simply does not have the throughput required for real time network control.

Feature comparison of Wi-Fi HaLow with Wi-Sun, LoRaWAN and eRECAP

LoRa WAN is another technology commonly found in smart infrastructures. Known for its low power, long range communication, LoRa WAN is effective in remote areas but struggles with limited bandwidth and latency, making it less suited for real-time energy management. When comparing Wi-Fi HaLow to LoRa WAN, one can see essentially the same issue as Wi-SUN; the throughput is not high enough for real-time networking.

Finally, LTE and 5G, while providing higher throughput, come with higher energy demands and greater cost, making them less practical for widespread smart meter deployments. LTE has the range and throughput required for future meter needs.

However, the modems tend to be more expensive and there is generally a variable cost per megabit of data. Additionally, LTE is a licensed spectrum so a utility provider would need to work with a given LTE carrier to ride on their network. This creates complexities and costs from a business model perspective.

However, it can eliminate the big cost of maintaining a separate network. Another option is private LTE. Here there are complexities for networks on a large scale. To date, they seem to be more effective in a small municipal utility environment or in geographies that have nationalised carriers and utilities.

The chart above shows a comparison to 5G eREDCAP, a reduced capability version of 5G in the sub-6GHz band. eREDCAP is the future for devices in the LTE NB-IOT class of devices. It uses lower power modes and single antenna solutions at 64QAM. Essentially it is 5G detuned for IoT applications.

It will have lower cost, lower complexity and lower throughput.  It was just approved in the summer of 2024 via 3GPP release 18. It is expected the networks will be software updated during late 2024 with optimised devices coming out in late 2025. As such, it is the best mobile technology to use in the comparison for the future meters.

The two significant issues with eREDCAP are as follows. First, it is still a ‘pay for Mbits’ technology and as more data is transmitted, the higher the cost will be. Secondly is consistent availability and coverage. While the 5G networks can be upgraded via software, much of the world is still 4G LTE only and a more complete conversion to 5G is expected to take over five years. That adds considerable uncertainty to the deployment model. That being said, for some locations, applications and geographies, eREDCAP will likely be the right solution.

In conclusion, no one technology will be the only solution for the needs of smart grid. Wi-Fi HaLow, with its sub-GHz operation, longer range, lower power consumption and ability to handle thousands of devices per access point, can complete LAN/WAN infrastructures. It provides the coverage and penetration needed for both rural and urban areas without the limitations of LoRa or the infrastructure complexity of Wi-SUN.

Additionally, Wi-Fi HaLow delivers robust connectivity at lower costs compared to LTE or 5G, making it an ideal solution for the evolving needs of smart grids, from real-time energy control to behind-the-meter services.

About the author

Tim Colleran is the smart grid market development director for Morse Micro. His career has extensively covered semiconductors and wireless technology and over the past 15 years he has been more closely affiliated with wireless smart energy and IoT.